Halo 4 is a treasure trove of secrets, from the crude to the touching to the utterly absurd. The hard part is finding them all. With CVG's help, you needn't waste hours on a fruitless hunt when we've wasted plenty for you. Read on for everything we've discovered so far. Oh, and SPOILERS AHEAD.
1. Master Chief unmasked
Let's start with the big one: MC's face. Finish Halo 4 on normal and you'll get a cutscene of the battle-hardened Spartan removing his Molinjor armour, but the camera cuts to black just before the money shot. Complete it on legendary difficulty, however, and you'll be awarded with the extended version where, after the famous Mark VI helmet lifts, you'll see John-117's mug in all its glory (well, his weary eyes, anyway). It chimes with a story which explores the rocky relationship between men and machines, and proves, after all, the Chief really is a person under the suit.
2. Holographic teabag
It's one of the FPS genres' most caustic gestures - crouching repeatedly over the dead body of an enemy to really rub the salt in - and that's why we love it. With Halo 4, you can perform the homoerotic dance from complete safety. Aim a holographic decoy (one of your armour abilities) at a fallen foe and it'll automatically perform what more polite gamers have come to call a 'victory crouch'. Warning: only to be used in instances of sheer butt-hurtery.
3. Avatar awards
Forget that waistcoat and baseball cap combo your poor Xbox Avatar's been decked in - Halo 4 serves up brand new outfits to try on for size. The Knight helmet is awarded for snagging the 'Knight in White Assassination' achievement (assassinate a Knight in any Spartan Ops mission); the platinum Mark VI helmet is given to those who finish the story; and a fetching avocado-green UNSC Infinity hoody is yours if you rank up to SR-5 in multiplayer component War Games.
4. Conan O'Brien
Coco and his sidekick Andy Richter cameo in Halo 4 as surly UNSC soldiers. He's basically the American version of Jonathan Ross, who himself made an appearance in Halo 3, and the red-headed TV host is such a fan of games - which he reviews in his web series Clueless Gamer - he jumped at the chance for a guest spot. He and Richter are stationed in one corner of the hanger at the beginning of mission six, Shutdown, just behind the Warthogs. Dialogue ranges from experiences of workers unions and their crate-guarding duty to awakening giant evil deities. Try meleeing an extra line or two out of them.
5. Red vs. Blue
Rooster Teeth's enormously popular series of comic videos, Red vs. Blue, kickstarted the machinima movement and generated more than a few Halo sales in the process. 343 Industries repays the favour. In the fifth Spartan Ops mission, The Cauldron, look over the barricade just before the ramp and you'll find a box on the ground near lava. Shoot it to hear RvB's jingly-jangly theme. For further fan pleasure, towards the end of the mission, RvB mainstay Caboose even chimes in with a few braindead phrases over the radio.
6. Dancing grunts
Grunts are the jesters of the Halo universe. Enabling one game-modifying skull sets each headshot to the sounds of children's laughter and puffs of confetti, and there was even an easter egg in Halo 2 level The Arbiter where the little fellas shared a birthday party. Here, visit the campaign's seventh mission Composer, and just before you get the Mantis mech, look down at the Atrium from behind the glass to see a group of grunts strutting their stuff. And what do you know? Even a bunch of Jackals are joining the festivities.
7. Who inverted the stick?
There's a second secret hiding on this level - a marine struggling to overcome an unwieldy Mantis. Turns out the previous pilot had inverted the stick! We've all been there. To find him, once you reach the Atrium, veer left and ascend the ramp where two mechs are stationed, then head on up to hear the dialogue. Sure, he's mad now, but wait until he discovers we set that other mech to bumper jumper...#haloinjoke
8. Collector's edition
For those that didn't shell out for the 80 quid collectors edition, the folks at 343 Industries have kindly included a free version with every copy. Well, a virtual version, anyway. On the first level, Dawn, clear the section where Covenant dock with the ship (just after you see a fleet of Banshee bank towards you from behind glass) and on the floor to the left you'll see a 3D model of the game box on the ground. And there's even more, one outside the cryopod with the number 8 painted on it, and one outside the 15th. Right, that's 80 quid saved.
9. John-117's service record
Terminals are a recurring feature in Halo games, and there are plenty spread throughout this one. There's a very special one at the start, though, that's easy to miss. Upon exiting Forward Unto Dawn's cryopod, head for the catwalk. You'll see a set of stairs. At the bottom, there's a terminal which contains Master Chief's service record. That is, it recaps the entire events from Halo 1, 2 and 3 with a complete plot summary. A handy feature for those lost in the labyrinthian exploits of the Master Chief.
So, that's our list of all Halo 4's secrets... so far. Have you found any we've missed? Tell us in the comments and share the love!